US5834567A - Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof - Google Patents

Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof Download PDF

Info

Publication number
US5834567A
US5834567A US08/801,786 US80178697A US5834567A US 5834567 A US5834567 A US 5834567A US 80178697 A US80178697 A US 80178697A US 5834567 A US5834567 A US 5834567A
Authority
US
United States
Prior art keywords
biodegradable
copolymer
caprolactone
mol
epsilon
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US08/801,786
Other languages
English (en)
Inventor
Hajime Yasuda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daicel Corp
Original Assignee
Daicel Chemical Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP12058894A external-priority patent/JP3413957B2/ja
Priority claimed from JP33586294A external-priority patent/JPH08176288A/ja
Application filed by Daicel Chemical Industries Ltd filed Critical Daicel Chemical Industries Ltd
Priority to US08/801,786 priority Critical patent/US5834567A/en
Application granted granted Critical
Publication of US5834567A publication Critical patent/US5834567A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/78—Preparation processes
    • C08G63/82—Preparation processes characterised by the catalyst used
    • C08G63/823—Preparation processes characterised by the catalyst used for the preparation of polylactones or polylactides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/64—Polyesters containing both carboxylic ester groups and carbonate groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/66—Polyesters containing oxygen in the form of ether groups
    • C08G63/664—Polyesters containing oxygen in the form of ether groups derived from hydroxy carboxylic acids

Definitions

  • the present invention relates to a biodegradable copolymer and a biodegradable copolymer composition. Furthermore, the present invention relates to a biodegradable article molded from the copolymer or the copolymer composition. Still further, the present invention relates to a process for the preparation of a biodegradable lactone-carbonate random copolymer.
  • the present invention relates to a copolymer or a composition which is capable of being applied as materials for various molded containers such as bottles, trays, box-type packages, and various molded articles, such as films for laminating the inside of paper containers, films for wrapping, films for agricultural uses, fibers, lines for fishing, ropes, nonwoven clothing, nets for construction, etc., which are substantially disposed in surroundings or circumstances in view of purposes for the use thereof.
  • the lactone-carbonate random copolymer prepared by the process is also excellent in biodegradability and transparency, making it possible to be used as biodegradable articles and medical devices, etc.
  • synthetic high polymers have been used as materials for various molded articles because of their excellence in mechanical properties and moldability, etc., and low price.
  • molded articles cannot be naturally degraded even when disposed or buried, because of their durability, for example, weatherability, etc., and further, in the case when such articles are burned, these may damage incinerators because of the high-calorie energy generated in the burning thereof.
  • poly(epsilon-caprolactone)s are known, and a demand thereof in the market has increased because of being manufactured at a relatively low price and as a safe biodegradable resin.
  • biodegradation rate is largely affected by the conditions in surroundings or circumstances, specifically, soil or types of microorganisms and living concentrations thereof, and temperatures. Accordingly, it is supposed that such a biodegradation rate in poly(epsilon-caprolactone)s is not occasionally satisfied, depending upon the uses.
  • Japanese Patent Publication (Kokoku) No. 3396/1967 states that useful polymer products can be prepared by bulk polymerization, suspension polymerization, and solution polymerization using a larger mol % of a cyclic ester such as epsilon-caprolactone and a smaller mol % of a cyclic carbonate monomer such as 4,4-dimethyl-2,6-dioxacyclohexanone, and polymer products are useful for manufacturing grips for brushes, buttons, lamp stands, and toys, etc.
  • a cyclic ester such as epsilon-caprolactone
  • a cyclic carbonate monomer such as 4,4-dimethyl-2,6-dioxacyclohexanone
  • Kokoku No. 3396/1967 does not state that copolymers and copolymer compositions thereof described in the present invention are biodegradable, or that biodegradable articles molded therefrom.
  • Japanese Patent Unexamined Publication (Kokai) No. 294326/1990 states a process for the preparation of a block copolymer composed of a lactone monomer and a cyclic carbonate monomer in which there is employed an organometallic compound such as n-BuLi, etc., as an initiator. Furthermore, there is known a process for the preparation of a lactone-carbonate block copolymer in which there is employed a trimethyl aluminum-water complex or a rare earth metal as an initiator.
  • U.S. Pat. No. 3,301,824 discloses a process for the preparation of a homopolymer of a cyclic carbonate monomer and a graft polymer of a cyclic carbonate monomer and a lactone monomer using stannous chloride or tin octylate, etc., as catalysts.
  • Japanese Patent Unexamined Publication (Kokai) No. 502651/1991 also discloses the use of a copolymer having recurring carbonate units as bioresorbable medical devices capable of being assimilated by living bodies by degrading into biologically innocuous components after degradation or implantable and undegradable medical devices having affinity to blood and/or living bodies.
  • tin salts such as stannous octoate (2-ethyl-hexanoate), etc., as catalysts for preparing the random copolymer.
  • Japanese Patent Unexamined Publication (Kokai) No. 508627/1-993 discloses the use of a random copolymer composed of trimethylene carbonate and caprolactone as a biodegradable reservoir device.
  • Kokai No. 508627/1993 there are employed tin salts such as stannous octoate (2-ethyl-hexanoate) or stannous chloride, etc., as catalysts for preparing the random copolymer. More specifically, Kokai No.
  • a random copolymer composed of trimethylene carbonate and caprolactone as a biodegradable reservoir device or bioabsorbable pharmaceutical devices (e.g., a cylindrical capsule having a 2.4 mm outer diameter and a thickness of 0.1-0.3 mm) for a drug delivery system which can sustainably discharge medicines in living bodies.
  • caprolactone-carbonate copolymers exhibit biodegradability, bioabsorbability, and biostability, and provide mechanical strength, transparency, and moldability
  • lactone monomers and carbonate monomers must be absolutely and unfailingly copolymerized in the state of random.
  • an organic lithium, triethylaluminum-water based complexes, or rare earth element complexes are employed as initiators, only block copolymers having a high content of a block structure are prepared, and random copolymers cannot be prepared.
  • a process for the preparation of a lactone-carbonate random copolymer which comprises a ring-opening addition polymerization of an admixture composed of a lactone monomer and a cyclic carbonate monomer with a ring-opening initiator in the presence of a specified organic aluminum-based Lewis acid.
  • a first aspect of the present invention relates to a biodegradable copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural units and (B) from 95 to 1% by mol of oxetane structural units, said structural units being combined in the state of a block.
  • a second aspect of the present invention relates to a biodegradable copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or delta-varelolactone structural unit and (C) from 95 to 1% by mol of a dimethyltrimethylene carbonate structural unit, said structural units being combined in the state of a random block.
  • a third aspect of the present invention relates to a biodegradable polymer composition which comprises (D) from 60 to 95% by mol of a poly(epsilon-caprolactone) or poly(delta-valerolactone) and (E) from 40 to 5% by mol of a poly(oxetane).
  • a fourth aspect of the present invention relates to a biodegradable article molded from a copolymer in the first aspect.
  • a fifth aspect of the present invention relates to a biodegradable article molded from a copolymer in the second aspect.
  • a sixth aspect of the present invention relates to a biodegradable article molded from a copolymer composition in the third aspect.
  • a seventh aspect of the present invention relates to a process for the preparation of a lactone-carbonate random copolymer which comprises a ring-opening addition polymerization of an admixture composed of a lactone monomer and a cyclic carbonate monomer with a ring-opening initiator in the presence of an organic aluminum-based Lewis acid represented by general formula (I) ##STR2## wherein R is an alkyl group having a carbon number ranging from 1 to 4, y is independently selected from a substituted group, and p is any one of 1 2, and 3.
  • An eighth aspect of the present invention relates to a biodegradable copolymer composition
  • a biodegradable copolymer composition which comprises a lactone-carbonate random copolymer obtained by a ring-opening addition polymerization of an admixture composed of a lactone monomer and a cyclic carbonate monomer with a ring-opening initiator in the presence of an organic aluminum-based Lewis acid represented by general formula (I) ##STR3## wherein R is an alkyl group having a carbon number ranging from 1 to 4, y is independently selected from a substituted group, and p is any one of 1, 2, and 3.
  • FIG. 1 is a graph representing a remaining ratio of weight versus incubation time by an enzyme for degradation related to the copolymer obtained in Example 1.
  • FIG. 2 is a graph representing a remaining ratio of weight versus, incubation time without an enzyme for degradation in Example 2.
  • FIG. 3 is a graph representing a remaining ratio of weight versus incubation time by an enzyme for degradation related to the copolymer obtained in Example 3.
  • FIG. 4 is a graph representing a remaining ratio of weight versus incubation time without an enzyme for degradation related to the polymer obtained in Example 5.
  • FIG. 5 is a graph representing a remaining ratio of weight versus the time of period buried in active sludge related to the polymer obtained in Example 6.
  • FIG. 6 is a graph representing a remaining ratio of weight versus incubation time by an enzyme for degradation related to the copolymer obtained in Example 6.
  • FIG. 7 is a graph representing a remaining ratio of weight versus incubation time without an enzyme for degradation in Example 8.
  • FIG. 8 (Example 9) is a graph representing a remaining ratio of weight versus incubation time by the enzyme Lipase B for degradation related to the copolymer obtained in Example 6.
  • FIG. 9 is a graph representing a remaining ratio of weight versus incubation time by the enzyme Rhizopus delmer Lipase for degradation related to the copolymer obtained in Example 6.
  • FIG. 10 (A) is an 1H-NMR chart related to the components produced by degradation in Example 8 and FIG. 10 (B) is an 1H-NMR chart related to the caprolactone homopolymer (CL).
  • FIG. 11 is a graph representing a remaining ratio of weight versus incubation time by the enzyme for degradation related to the dimethyltrimethylene carbonate (DTC) homopolymer (Comparative Example 6), the valerolactone-dimethyltrimethylene carbonate (VL/DTC) block copolymer (Example 11), and the valerolactone (VL) homopolymer (Comparative Example 12).
  • DTC dimethyltrimethylene carbonate
  • VL/DTC valerolactone-dimethyltrimethylene carbonate
  • VL valerolactone
  • FIG. 12 is an 1H-NMR chart related to the random copolymer obtained in Example 14.
  • a biodegradable copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or a delta-valerolactone structural unit and (B) from 95 to 1% by mol of an oxetane structural unit, said structural units being combined in the state of a block.
  • a biodegradable copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural unit and (C) from 95 to 1% by mol of a dimethyltrimethylene carbonate structural unit, said structural units being combined in the state of a random block.
  • a biodegradable polymer composition which comprises (D) from 60 to 95% by mol of a poly(epsilon-caprolactone) or a poly(delta-valerolactone) and (E) from 40 to 5% by mol of a poly(oxetane).
  • a biodegradable article molded from a copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural unit and (B) from 95 to 1% by mol of an oxetane structural unit, said structural units being combined in the state of a block.
  • a biodegradable article molded from a copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 which comprises (A) from 5 to 99% by mol of epsilon-caprolactone or delta-varelolactone structural unit and (C) from 95 to 1% by mol of a dimethyltrimethylene carbonate structural unit, said structural units being combined in the state of a random block.
  • a biodegradable article molded from a biodegradable copolymer composition which comprises (D) from 60 to 95% by mol of a poly(epsilon-caprolactone) or poly(delta-varelolactone) and (E) from 40 to 5% by mol of a poly(oxetane).
  • Monomers to be employed in the biodegradable copolymers or composition, and the biodegradable articles of the present invention include epsilon-caprolactone, delta-varelolactone, oxetane (another name for this is trimethylene oxide or 1,3-epoxypropane), and dimethyltrimethylene carbonate (another name for this is 4,4-dimethyl-2,6-dioxacyclohexanone), which are essential structural units, respectively.
  • the biodegradable copolymer which is the first aspect of the present invention is an epsilon-caprolactone-oxetane copolymer or delta-varelolactone oxetane copolymer which is a block type.
  • the biodegradable copolymer which is the second aspect of the present invention is an epsilon-caprolactone-dimethyltrimethylene carbonate copolymer or delta-varelolactone-dimethyltrimethylene carbonate copolymer which is a block type.
  • the block copolymers are not particularly limited in the type of their block structures, which include a random block type, diblock type, triblock type, etc., and, further, these are classified into a linear type, branch type, and radial type.
  • the above-described block copolymers essentially have a number average molecular weight ranging from 1,000 to 1,000,000, preferably from 10,000 to 500,000, more preferably from 30,000 to 300,000 based on a standard polystyrene measured by a GPC.
  • the copolymers are frequently in liquid states at ordinary temperatures, unpreferably resulting in being incapable of using as molded articles.
  • it exceeds 1,000,000 it is substantially difficult to prepare the copolymers, and the biodegradability thereof would occasionally unpreferably lower.
  • the number average molecular weight preferably ranges from 30,000 to 300,000, more preferably from 50,000 to 200,000, from a viewpoint of a balance between mechanical properties, moldability, biodegradability, etc.
  • the content of the epsilon-caprolactone structural unit or delta-valerolactone structural unit in the above-described block copolymers generally ranges from 5 to 99% by mol, preferably from 50 to 98% by mol, more preferably from 70 to 95% by mol, based on the total contents containing the oxetane structural units or dimethyltrimethylene structural units.
  • a copolymer having a number average molecular weight ranging from 30,000 to 300,000, an epsilon-caprolactone structural unit or a delta-valerolactone structural unit ranging from 70 to 95% by mol and oxetane structural unit ranging from 30 to 5% by mol exhibits mechanical properties, thermal stability, and moldability, etc., equal to an epsilon-caprolactone or delta-valerolactone homopolymer, and it is particularly excellent also in biodegradability.
  • the bond between the epsilon-caprolactone structural unit and the oxetane structural unit is represented by --CO--(CH 2 ) 5 --O--(CH 2 ) 3 --O--, and similarly, the bond between the delta-valerolactone structural unit and the oxetane structural unit is represented by --CO--(CH 2 ) 4 --O--(CH 2 ) 3 --O-- which essentially constitutes the biodegradable copolymer which is the first aspect of the present invention.
  • the bond between the epsilon-caprolactone structural unit and the dimethyltrimethylene carbonate structural unit is represented by --CO--(CH 2 ) 5 --OCOOCH 2 C(CH 3 ) 2 --CH 2 O--, and similarly, the bond between the delta-valerolactone structural unit and the dimethyltrimethylene carbonate structural unit is represented by --CO--(CH 2 ) 4 --OCOOCH 2 C(CH 3 ) 2 --CH 2 O-- which essentially constitutes the biodegradable copolymer which is the second aspect of the present invention.
  • the biodegradable copolymers which are the first and second aspects of the present invention can be prepared without particular limitations, that is, the copolymers are prepared by any processes in which epsilon-caprolactone or delta-valerolactone can be copolymerized with oxetane or dimethyltrimethylene carbonate. Specifically, there are preferred processes using an organometallic compound which is an initiator.
  • the organometallic compound there are specifically exemplified trialkylaluminum-water based complexes, zinc dialkylate-water based complexes, alkyl lithiums, organic potassium compounds, and organic sodium compounds.
  • trialkylaluminum-water based complexes more specifically, triethyl aluminum-water based complexes are preferably employed.
  • the molar ratio of water/trialkylaluminum ranges preferably from 0.7 to 1.1.
  • oxetane is not readily copolymerized with epsilon-caprolactone due to the difference of the copolymerization rate between oxetane and epsilon-caprolactone.
  • oxetane alone is partially or totally polymerized using a triethyl aluminum-water-based complex as an initiator at a temperature ranging from -20° to 40° C., and then epsilon-caprolactone is charged to copolymerize with the resulting oxetane homopolymer at a temperature ranging from 0° to 180° C., preferably from 50° to 150° C.
  • oxetane can be copolymerized with delta-varelolactone due to a similar copolymerization rate between oxetane and delta-varelolactone. Accordingly, there is preferably carried out a process in which oxetane and delta-valerolactone can be simultaneously charged to copolymerize using a triethyl aluminum-water-based complex as an initiator at a temperature ranging from 0° to 180° C.
  • the copolymerization of epsilon-caprolactone or delta-valerolactone with dimethyl trimethylene carbonate can be carried out by mixing these with each other, followed by feeding a triethyl aluminum-water-based complex as an initiator, at a temperature ranging from 0° to 180° C.
  • biodegradable copolymers of the first and second aspect of the present invention can be prepared without any limitations using popular polymerization procedures and equipment for the preparation.
  • the solvents in the above-described solution polymerization there are employed aromatic hydrocarbons such as benzene, toluene, xylene, etc., ethers such as diethylether, etc.
  • the solvents can be mixed with aliphatic hydrocarbons such as hexane, heptane, cyclohexane, etc., in a range capable of dissolving the resulting polymers.
  • a continuous, semicontinuous, and batch-type equipment there can be employed a continuous, semicontinuous, and batch-type equipment without any problem.
  • a Sultzer-mixer type or an extruder type continuous-polymerization equipment is preferably employed in bulk polymerization, in view of the capability of economically manufacturing the biodegradable copolymer of the present invention on a large scale.
  • polymerization are preferably carried out in a temperature ranging from 40° to 180° C., and preferably from 100° to 170° C.
  • solution polymerization or sedimentation polymerization it is preferably carried out in a temperature ranging from -20° C. to the boiling points of solvents.
  • the content of a block-type polymer would be unpreferably lowered, and polymerization rate would be unpreferably slow.
  • the polymerization system would be unpreferably maintained at compressed conditions.
  • biodegradable copolymers of the first and second aspect in the present invention other copolymerizable monomers can be employed together with epsilon-caprolactone, delta-valerolactone, dimethyl trimethylene carbonate, and oxetane.
  • Examples of other copolymerizable monomers include ethylene oxide, propylene oxide, tetrahydrofran, cyclic ethers such as dioxane or trioxane, beta-propiolactone, methylated caprolactone, lactones other than epsilon-caprolactone or delta-valerolactone, lactide which is a dimer of lactic acid, glicolides, cyclic carbonates such as trimethylene carbonate and methyltrimethylene carbonate, etc.
  • biodegradable copolymers of the first and second aspect in the present invention can be also mixed with each other, and further with other biodegradable or unbiodegradable thermoplastics in any mixing ratio.
  • biodegradable thermoplastics include a polylactic acid, a polyglicolide, an aliphatic polyester, polylactones such as a poly(epsilon-caprolactone) or a poly(delta-valerolactone), starch, celluloses, and hydroxyethyl celluloses, etc.
  • the biodegradable polymer composition of the third aspect in the present invention is a mixed composition composed of poly(epsilon-caprolactone) homopolymer or a poly(delta-valerolactone) homopolymer and a poly(oxetane) homopolymer.
  • the poly(oxetane) homopolymer is employed in an amount ranging from 5 to 40 mol % based on the total amount.
  • mol % shows the content of oxetane units based on 100 mol % of each monomer unit in the homopolymers.
  • Number average molecular weight in all of the homopolymers to be mixed ranges from 20,000 to 1,000,000, preferably from 30,000 to 500,000, and more preferably from 50,000 to 200,000.
  • the biodegradable polymer composition of the third aspect in the present invention also includes a three-homopolymer admixture composed of a poly(epsilon-caprolactone) homopolymer, a poly(delta-valerolactone) homopolymer, and a poly(oxetane) homopolymer.
  • a process for mixing the homopolymers is not limited, a conventional melt kneader such as an extruder can be preferably employed in an industrial fashion.
  • biodegradable copolymers of the first and second aspect and the biodegradable polymer composition of the third aspect in the present invention can provide the biodegradable articles of the fourth, fifth and sixth aspect, respectively.
  • the biodegradable articles can be molded from biodegradable copolymers and the biodegradable polymer composition.
  • Biodegradable articles include all products which are usually left consciously or unconsciously in living circumstances from the viewpoint of usage.
  • the products include, for example, materials for agricultural uses such as films or nonwoven clothing, textiles, ropes, materials such as films or nonwoven clothes for engineering works, materials such as nets for construction use, materials such as oil spill blotters for protecting the environment, materials such as lines or nets for fishing, various foam materials (for example, life preservers, materials for cushions, buoys or markers for fishing nets, etc), coatings for ships (coatings for bottom of ships), films for protecting bottom of boats, bottles, trays, various containers such as box-type packages, internal films for laminating on paper containers, wrapping films for waste or shopping, cushion materials or protective films for goods to be exported (electrical appliances, precision parts, large-scale equipments), etc.
  • a process for the preparation of a lactone-carbonate random copolymer which comprises a ring-opening addition polymerization of an admixture composed of a lactone monomer and a cyclic carbonate monomer with a ring-opening initiator in the presence of an organic aluminum-based Lewis acid represented by general formula (I); ##STR4## wherein R is an alkyl group having a carbon number ranging from 1 to 4, Y is independently selected from a substituted group, and p is any one of 1, 2 and 3.
  • a biodegradable copolymer composition which comprises a lactone-carbonate random copolymer obtained by a ring-opening addition polymerization of an admixture composed of a lactone monomer and a cyclic carbonate monomer with a ring-opening initiator in the presence of an organic aluminum-based Lewis acid represented by general formula (I); ##STR5## wherein R is an alkyl group having a carbon number ranging from 1 to 4, Y is independently selected from a substituted group, and p is any one of 1, 2 and 3.
  • Ring-opening initiators in the present invention include a compound having at least one active hydrogen atoms such as a hydroxyl group, amino group, carboxylic group, thiol group, and an active methylene group put between at least two electron-attractive groups in the molecule.
  • aliphatic alcohols and aliphatic polyvalent alcohols. More specifically, there are exemplified methanol, ethanol, isopropanol, ethyleneglycol, diethyleneglycol, butanediol, hexamethyleneglycol, neopentyl glycol, trimethylolpropane, pentaerythritol, 2-hydroxyethyl(meth)-acrylate, 4-hydroxybutyl(meth)acrylate, allylalcohol, a polyvinylalcohol, a 2-hydroxyethyl(meth)acrylate-modified polymer, and an adduct of ethylene oxide to bisphenol A, and the like.
  • lactone monomers in the present invention there can be generally employed publicly known lactones and, specifically, delta-valerolactone, epsilon-caprolactone, and an alkylated lactone thereof are preferably employed from a general or practical viewpoint. Of these, epsilon-caprolactone is preferably employed because it is manufactured industrially. One or more of the lactone monomers may be employed.
  • cyclic carbonate monomers there can be preferably employed propylglycol carbonate, 2-methylpropylglycol carbonate, neopentyl glycol carbonate, and the like.
  • One or more of the cyclic carbonate monomers may be employed.
  • Mixing ratio between the lactone monomer and the cyclic carbonate monomer is not particularly limited, both monomers are employed in an amount ranging from 10 to 90 parts by weight, preferably from 20 to 80 parts by weight, respectively, and more preferably one monomer is employed in an amount ranging from 20 to 40 parts by weight, and another monomer is employed in an amount ranging from 80 to 60 parts by weight.
  • Admixture composed of the lactone monomer and the cyclic carbonate monomer is employed in a molar ratio ranging from 1 to 10,000, preferably from 100 to 5,000, and more preferably from 500 to 2,000 based on 1 mol of initiators.
  • the organic aluminum-based Lewis acid in the present invention is represented by the above-described general formula (I).
  • R is an alkyl group having a carbon number ranging from 1 to 4
  • Y is independently selected from a substituted group
  • p is any one of 1, 2, and 3.
  • the alkyl group R specifically includes the methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, and tert-butyl group.
  • Specific examples of the substituted group Y independently include hydrogen, an alkyl group such as a methyl group, ethyl group, butyl group, and tert-butyl group, and the like, an aryl group such as the phenyl group, and the like, a halogen such as fluorine, chlorine, and iodine, and the like, a trimethylsilyl group, and a trimethylgelmil group, and the like.
  • p is any one of 1, 2, and 3.
  • p is 1, although the ring-opening addition reaction rate of the cyclic monomers becomes large, there is exhibited a tendency lowering the random structure content in the resulting copolymer and further, in the case when p is 3, it is difficult to prepare catalysts, resulting in that p is most preferably 2.
  • the organic aluminum-based Lewis acid in the seventh aspect of the present invention represented by above-described general formula (I) can be prepared by a reaction of an alkylphenol such as 2,6-diphenylphenol, 2,6-ditert-butyl-4-methylphenol, and 2,4,6-trichlorophenol, etc. with a trialkylaluminum such as tri-methylaluminum and triisobutylaluminum, etc.
  • an alkylphenol such as 2,6-diphenylphenol, 2,6-ditert-butyl-4-methylphenol, and 2,4,6-trichlorophenol, etc.
  • a trialkylaluminum such as tri-methylaluminum and triisobutylaluminum, etc.
  • an excessive amount of alkylphenol is allowed to react with the trialkylaluminum, specifically, in a molar ratio ranging from 5/1 to 1/1, preferably from 2.5/1 to 2/1.
  • the reaction is preferably carried out in a temperature ranging from 0° C. to room temperatures.
  • the organic aluminum-based Lewis acid is obtained in the state of a white-colored crystalline after washing with an inert solvent such as hexane or in the state of a solution thereof.
  • an organic aluminum-based Lewis acid represented by general formula (II) as described below is preferably employed. ##STR6##
  • R is an alkyl group having a carbon number ranging from 1 to 4, X is independently chosen among the tert-butyl group, phenyl group, chlorine, bromine, and iodine. Y is independently any appropriate substituted groups as indicated for the formula (I).
  • X is chosen among groups such as a hydrogen and methyl group, the catalysts become sterically less hindered each other, thus giving rise to associability so that the coordinating effect of the lactone monomer, the cyclic carbonate monomer, and the admixture thereof on the catalysts decreases. Therefore, to obtain a highly random copolymer having an excellent biodegradability, X is preferably chosen among the groups which are indicated for the formula (II).
  • the organic aluminum-based Lewis acid represented by general formula. (I) is employed in a molar ratio ranging from 0.0001 to 1, preferably from 0.001 to 0.5, more preferably from 0.05 to 0.2 based on 1 mol of the initiators. In the case when the molar ratio is less than 0.0001, the ring-opening reaction of the cyclic monomers is slow, and in the case when it exceeds 1, it is meaninglessly only excessive in a practical manner.
  • improved apparatuses for the preparation are preferably employed so that the mixing of moisture and other impurities into starting materials can be prevented.
  • the total amount of the above-described impurities including moisture is desirably controlled within an amount of less than 5,000 ppm, preferably less than 500 ppm, and more preferably less than 50 ppm based on the total amount of starting materials.
  • solvents may also be employed.
  • solvents there are exemplified aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and the like, aromatic hydrocarbons such as benzene, toluene, xylene, and the like, and halogenated hydrocarbons such as chloroform, dichloromethane, and the like which do not have an active hydrogen atom such as hydroxyl group.
  • aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and the like
  • aromatic hydrocarbons such as benzene, toluene, xylene, and the like
  • halogenated hydrocarbons such as chloroform, dichloromethane, and the like which do not have an active hydrogen atom such as hydroxyl group.
  • the solvents may be preferably employed in an appropriate amount without any limitations.
  • the initiators, the lactone monomer and cyclic carbonate monomer which are the starting materials in the present invention, catalysts, and optional solvents may be fed into a reaction vessel in any order without any limitations for methods to be fed.
  • a reaction may be carried out at temperatures ranging from 0° to 200° C., and preferably from room temperatures to 180° C. or so. Even in the case when the reaction is carried out at more than 180° C., although the reaction can be carried out, the reaction rate is unpreferably lowered at temperatures higher than the initiation of decomposition of the organic aluminum-based Lewis acid.
  • the reaction is not particularly limited by other conditions except the above-described conditions.
  • an organic aluminum-based Lewis acid which is a catalyst may also be optionally separated from copolymers produced after the completion of the ring-opening addition reaction.
  • solvent separation there are exemplified solvent separation, absorption, distillation or evaporation at reduced pressures, and filtration, and the like.
  • solvent separation process there can be carried out all of the methods in which the difference in solubility between copolymers produced and the organic aluminum-based Lewis acid is applied.
  • chromatography in which there are employed substrates such as activated carbon, silica gel, alumina, graphite, a polymer having hydroxyl group, amino group, carboxylic group, and sulfoxide group, and the like, and a porous ceramic, and, further, an electrophoresis method.
  • substrates such as activated carbon, silica gel, alumina, graphite, a polymer having hydroxyl group, amino group, carboxylic group, and sulfoxide group, and the like, and a porous ceramic, and, further, an electrophoresis method.
  • a membrane process can be applied using the difference in molecular sizes.
  • oxetane (referred to as Ox in the Table) was firstly polymerized in a bulk state at 0° C. for 12 hours using 0.2% by mol of a triethylaluminum-water (1/0.75) based complex as an initiator based on the total amount of the monomers.
  • Films having 1 cm ⁇ 1 cm ⁇ 500 ⁇ m were prepared from the copolymers and the homopolymers obtained in Example 1 and Comparative Example 1, and then the films were placed in a sample bottle filled with 10 milliliter of a buffer solution (pH 7.2) composed of phosphoric acid having 0.1M, and then there was added 8 ⁇ g of Cholesterol esterase which is an enzyme for degradation. Successively, the sample bottle was warmed at 37° C. and pH 7.2 for 200-300 hours in an incubator, and remained films were taken out, followed by measuring the remaining ratio of the weight after washing with water and freezedly drying. The results are shown in FIG. 1.
  • FIG. 1 shows that biological degradation rate is high in the two samples prepared from the block copolymers having 9 mol % and 20 mol % of oxetane contents (hereinafter, referred to as oxetane/CL in Figures) compared to the poly(epsilon-caprolactone) homopolymers.
  • oxetane and delta-valerolactone (referred to as VL in Table and Figure) were mixed, and polymerized in a bulk state at 60° C. for 24 hours using 0.2% by mol of a triethylaluminum-water (1/0.75) based complex as an initiator based on the total amount of the monomers.
  • a delta-valerolactone homopolymer was prepared in toluene using 1.0% by mol of a diethylzinc-hydrogen complex as an initiator at 60° C. for 15 days while stirring, and analyzed according to the same conditions as in Example 3, and the results are shown in Table 2.
  • the epsilon-caprolactone homopolymer and oxetane homopolymer obtained in Comparative Example 1 were mixed according to the molar ratio as described in FIG. 4, followed by dissolving into chloroform and evaporating chloroform to obtain a film composed of the mixed polymers.
  • the film was employed to evaluate biodegradability according to the same procedures as in Example 2. The results obtained are shown in FIG. 4. It was confirmed that even a blended polymer composed of the epsilon-caprolactone homopolymer and oxetane homopolymer exhibits a better biodegradability than the respective homopolymers depending upon blend ratio.
  • Epsilon-caprolactone, dimethyltrimethylene carbonate (referred to as DTC in Table and Figure), and toluene were mixed and copolymerized at 60° C. for 4 hours using 0.2% by mol of a triethylaluminum-water (1/0.75) based complex as an initiator based on the total amount of the monomers.
  • copolymers exhibit a better biodegradability than the epsilon-caprolactone homopolymer.
  • Example 6 The copolymers and the epsilon-caprolactone homopolymers obtained in Example 6 and Comparative Example 6, respectively, were employed to evaluate a biodegradability according to the same conditions as described in Example 2. The results obtained are shown in FIG. 6. Furthermore, the same tests were carried out without any enzymes. As shown in FIG. 7, weight loss was almost no observed in all the samples.
  • Example 8 was repeated except that the copolymers and the homopolymers obtained in Example 6 and Comparative Example 6, respectively, were employed, and the enzyme Rhizopus delemer Lipase B (pH 9.0, 37° C.) for degradation was employed in place of the enzyme Cholesterol esterase (pH 7.2). The results obtained are shown in FIGS. 7 and 8, respectively.
  • FIG. 10(A) is an 1 H-NMR chart. Furthermore, FIG. 10(B) is an 1 H-NMR chart concerning degradation components generated from the epsilon-caprolactone homopolymer.
  • Delta-varelolactone, dimethyltrimethylene carbonate, and toluene were mixed and copolymerized at 60° C. for 4 hours using 0.2% by mol of a triethylaluminum-water (1/0.75) based complex as an initiator based on the total amount of the monomers.
  • a delta-valerolactone homopolymer was prepared according to the same conditions as in Example 6. Molecular weight of the homopolymer is shown in Table 4.
  • Example 2 was repeated except that the copolymers and the homopolymers obtained in Comparative Example 6, Example 11, and Comparative Example 12, respectively, were employed to evaluate biodegradability. The results obtained are shown in FIG. 11.
  • 2,6-ditert-butyl-methylphenol (2.76 g, 12.5 millimole) was dissolved into 10 ml of dried hexane, and then trimethyl-aluminum (0.6 ml, 6.25 millimole) was added dropwise at 0° C. to obtain a suspension.
  • the suspension obtained was heated to 60° C. in order to dissolve it. After the suspension was completely dissolved, it was placed for 10 hours at room temperatures to obtain an aluminum-based Lewis acid substituted by two-fold by mol of 2,6-ditert-butyl-methylphenol (hereinafter, referred to as MeAlBMP) which is a white-colored crystalline.
  • MeAlBMP 2,6-ditert-butyl-methylphenol
  • a 1-liter dried flask made of glass was charged with 0.186 g (3 millimole) of ethylene glycol as an initiator, 428 g (3.75 mol) of epsilon-caprolactone as a lactone monomer, 162.5 g (1.25 mol) of neopentyl glycol carbonate as a cyclic carbonate monomer, and 0.295 g (500 ppm) of MeAlBMP obtained in the Reference Example 1 as an aluminum-based Lewis acid catalyst, while purging with dried nitrogen gas, followed by stirring at 140° C. for 3 hours to obtain a transparent lactone-carbonate random copolymer.
  • the random copolymer obtained was analyzed with a GPC to obtain a number average molecular weight of 187,000 and molecular weight distribution (Mn/Mw) of 1.28 based on a standard Polystyrene.
  • FIG. 12 is an 1 H-NMR chart related to the random copolymer, and shows that the molar ratio of epsilon-caprolactone/neopentyl glycol carbonate in the copolymerization is 76/24.
  • a 1-liter dried flask made of glass was charged with 0.62 g (10 millimole) of ethylene glycol as an initiator, 342.4 g (3 mol) of epsilon-caprolactone and 128.2 g (1 mol) of 4-methyl-epsilon-caprolactone as lactone monomers, 130.1 g (1 mol) of neopentyl glycol carbonate as a cyclic carbonate monomer, and 0.12 g (200 ppm) of MeAlBMP obtained in the Reference Example 1 as an aluminum-based Lewis acid catalyst, while purging with dried nitrogen gas, followed by stirring at 100° C. for 12 hours to obtain a colorless transparent lactone-carbonate random copolymer.
  • the random copolymer obtained was analyzed with a GPC to obtain a number average molecular weight of 59,000 and molecular weight distribution (Mn/Mw) of 1.22 based on a standard Polystyrene. Furthermore, unreacted monomers were not detected.
  • Example 13 For reference, the same procedures as in Example 13 were repeated except that 0.295 g (500 ppm) of stannous octoate described in the WO89/5664 Publication and WO91/16887 was employed as a catalyst to prepare a random copolymer in place of MeAlBMP. Even after reacting while stirring at 140° C. for 3 hours, as a large amount of monomers were remained, the reaction was further continued. After 48 hours, as epsilon-caprolactone in the random copolymer decreased to less than 1%, the reaction was terminated. Although the random copolymer was transparent, it was slightly yellowed.
  • Example 7 and Comparative Example 7 were repeated except that there were employed films having 30 cm ⁇ 30 cm ⁇ 0.5 mm prepared from the lactone-carbonate random copolymer prepared in Example 13 and an epsilon-caprolactone homopolymer having a number average molecular weight of 100,00 (PLACCEL H-7 DD001 manufactured by Daicel Chemical Industries, Ltd.) for reference. Films buried in an activated sludge were taken out at a fixed interval over 200 days, and the films were washed with water, followed by being freezedly dried to evaluate retention ratio of the weight.
  • PLACCEL H-7 DD001 manufactured by Daicel Chemical Industries, Ltd.
  • FIG. 12 shows that the lactone-carbonate random copolymer exhibits more excellent biodegradability than the epsilon-caprolactone homopolymer.
US08/801,786 1994-05-09 1997-02-18 Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof Expired - Fee Related US5834567A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US08/801,786 US5834567A (en) 1994-05-09 1997-02-18 Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP12058894A JP3413957B2 (ja) 1994-05-09 1994-05-09 易生分解性共重合体、重合体組成物および環境放置型成形品
JP6-120588 1994-05-09
JP6-335862 1994-12-21
JP33586294A JPH08176288A (ja) 1994-12-21 1994-12-21 ラクトン−カーボネートランダム共重合体の製造方法
US43419595A 1995-05-03 1995-05-03
US08/801,786 US5834567A (en) 1994-05-09 1997-02-18 Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US43419595A Continuation 1994-05-09 1995-05-03

Publications (1)

Publication Number Publication Date
US5834567A true US5834567A (en) 1998-11-10

Family

ID=26458135

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/801,786 Expired - Fee Related US5834567A (en) 1994-05-09 1997-02-18 Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof

Country Status (3)

Country Link
US (1) US5834567A (de)
EP (1) EP0682054B1 (de)
DE (1) DE69522038T2 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030069629A1 (en) * 2001-06-01 2003-04-10 Jadhav Balkrishna S. Bioresorbable medical devices
US20080127857A1 (en) * 2001-04-20 2008-06-05 The Lubrizol Corporation Dispersants
US20080161489A1 (en) * 2006-12-28 2008-07-03 Adel Farhan Halasa Rubbery block polymers containing polylactone and rubber compounds including the same
US20140148558A1 (en) * 2010-09-21 2014-05-29 Centre National De La Recherche Scientifique(Cnrs) One-step, one-pot process for preparing multiblock and gradient copolymer
CN112375206A (zh) * 2020-12-22 2021-02-19 浙江兆泽实业有限公司 一种皮革用高物性无溶剂聚氨酯面料树脂及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19924747B4 (de) * 1999-05-31 2014-07-17 Dynamit Nobel Gmbh Explosivstoff- Und Systemtechnik Bleifreies Geschoß mit nach Anforderung einstellbarer Dichte

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3489819A (en) * 1967-07-19 1970-01-13 Phillips Petroleum Co Block copolymers comprising a lactone and tetrahydrofuran
US3689531A (en) * 1969-04-01 1972-09-05 Union Carbide Corp Copolymers of lactones and alkylene oxides
JPH05262858A (ja) * 1992-03-18 1993-10-12 Shiro Kobayashi 新規なブロック共重合体及びその製造法
US5352515A (en) * 1992-03-02 1994-10-04 American Cyanamid Company Coating for tissue drag reduction

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3301824A (en) 1963-09-26 1967-01-31 Union Carbide Corp Polymers of cyclic carbonates
US4605730A (en) * 1982-10-01 1986-08-12 Ethicon, Inc. Surgical articles of copolymers of glycolide and ε-caprolactone and methods of producing the same
JP2868817B2 (ja) 1987-12-17 1999-03-10 ユナイテッド・ステーツ・サージカル・コーポレーション 反復カーボネート単位を含むホモポリマーおよびコポリマーから製造された医療用具
DE3911557A1 (de) 1989-04-08 1990-10-11 Bayer Ag Blockcopolymere
ES2075450T3 (es) 1990-05-01 1995-10-01 Res Triangle Inst Poliesteres biodegradables para el suministro prolongado de farmacos.
US5132397A (en) * 1991-04-02 1992-07-21 Polysar Financial Services S.A. 4-valerolactone copolymers
EP0509203A3 (en) * 1991-04-17 1993-04-14 Christian Dr. Med. Juergens Resorbable, physiologically acceptable copolymers and their use
NL9102148A (nl) * 1991-12-20 1993-07-16 Dsm Nv Copolymeer van lacton en carbonaat en werkwijze voor het verkrijgen ervan.
JP3414029B2 (ja) * 1994-03-04 2003-06-09 ダイセル化学工業株式会社 単分散重合体およびそれらの製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3489819A (en) * 1967-07-19 1970-01-13 Phillips Petroleum Co Block copolymers comprising a lactone and tetrahydrofuran
US3689531A (en) * 1969-04-01 1972-09-05 Union Carbide Corp Copolymers of lactones and alkylene oxides
US5352515A (en) * 1992-03-02 1994-10-04 American Cyanamid Company Coating for tissue drag reduction
JPH05262858A (ja) * 1992-03-18 1993-10-12 Shiro Kobayashi 新規なブロック共重合体及びその製造法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Duda "Preparation of Telechelic Polyester Oligodiols" Macromolecules 27(2); 1994 pp. 576-582.
Duda Preparation of Telechelic Polyester Oligodiols Macromolecules 27(2); 1994 pp. 576 582. *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080127857A1 (en) * 2001-04-20 2008-06-05 The Lubrizol Corporation Dispersants
US8076378B2 (en) * 2001-04-20 2011-12-13 The Lubrizol Corporation Dispersants
US20030069629A1 (en) * 2001-06-01 2003-04-10 Jadhav Balkrishna S. Bioresorbable medical devices
US20080161489A1 (en) * 2006-12-28 2008-07-03 Adel Farhan Halasa Rubbery block polymers containing polylactone and rubber compounds including the same
US7662883B2 (en) 2006-12-28 2010-02-16 The Goodyear Tire & Rubber Company Rubbery block polymers containing polylactone and rubber compounds including the same
US20140148558A1 (en) * 2010-09-21 2014-05-29 Centre National De La Recherche Scientifique(Cnrs) One-step, one-pot process for preparing multiblock and gradient copolymer
US9493606B2 (en) * 2010-09-21 2016-11-15 Total Research & Technology Feluy One-step, one-pot process for preparing multiblock and gradient copolymer
CN112375206A (zh) * 2020-12-22 2021-02-19 浙江兆泽实业有限公司 一种皮革用高物性无溶剂聚氨酯面料树脂及其制备方法

Also Published As

Publication number Publication date
DE69522038T2 (de) 2002-03-14
DE69522038D1 (de) 2001-09-13
EP0682054A3 (de) 1996-01-31
EP0682054B1 (de) 2001-08-08
EP0682054A2 (de) 1995-11-15

Similar Documents

Publication Publication Date Title
US5461139A (en) Biodegradable optically active copolymers and processes for producing the same
US5824751A (en) Biodegradable high molecular composition
Coulembier et al. From controlled ring-opening polymerization to biodegradable aliphatic polyester: Especially poly (β-malic acid) derivatives
US6228969B1 (en) Biodegradable polyester urethanes, method for the production and use thereof
US4983689A (en) Process for making macromolecular monomers of polylactones with terminal acryloyl unsaturation and block copolymers thereof
US4644038A (en) Unsaturated poly (alpha-hydroxy acid) copolymers
US5834567A (en) Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof
Maeda et al. Synthesis and characterization of novel biodegradable copolyesters by transreaction of poly (ethylene terephthalate) with copoly (succinic anhydride/ethylene oxide)
US5631344A (en) Block copolymer of polyesters and polycarbonates and process for preparation thereof
US5840811A (en) Optically active block polyester copolymer and method for production thereof
Shirahama et al. Biodegradation of novel optically active polyesters synthesized by copolymerization of (R)-MOHEL with lactones
Kunioka et al. Polymerization of poly (ε-caprolactone) using yttrium triflate
JPH05132549A (ja) 新規生分解性重合体及び組成物
JP3408349B2 (ja) 生分解性高分子用可塑剤
JP3413957B2 (ja) 易生分解性共重合体、重合体組成物および環境放置型成形品
JPH04114029A (ja) ラクトン共重合体およびその製造方法
JP3142658B2 (ja) 生分解性光学活性ポリエステルおよびその製造方法
JP2794353B2 (ja) 生分解性光学活性ポリマーおよびその製造方法
US6143801A (en) Catalyst for ester metathesis
JP3492053B2 (ja) 生分解性高分子組成物用相容化剤
JP3407767B2 (ja) 透明な乳酸系共重合ポリエステルの製造方法及び包装材料
JPH06336519A (ja) ポリエチレンサクシネート及びその製造方法
KR100200415B1 (ko) 생분해성 지방족 폴리에스터 제조방법
JP3345631B2 (ja) 生分解性を有する樹脂の製法
US20020052458A1 (en) Process for producing b-butyrolactone homopolymer or copolymer

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20101110